1. Field of the Invention
The present disclosure relates to pressure control in a vegetable room of a refrigerator, and particularly, to a vegetable room of a refrigerator in which pressure is controlled according to vegetable, fruit, and mixture modes. More particularly, the present disclosure relates to a vegetable room of a refrigerator in which different pressures are applied according to vegetable, fruit, and mixture modes such that each pressure corresponds to storage conditions of storage items such as vegetable and fruit stored in an airtight state therein, whereby each storage item is maintained with optimal freshness.
2. Background of the Invention
In general, a refrigerator is equipment for keeping food items in storage in a low-temperature state for a long period of time by generating cold air by driving a refrigerating cycle installed therein and supplying generated cold air to the interior of a refrigerating chamber and a freezing chamber.
In general, as illustrated in FIG. 1, a refrigerator 1 includes a freezing chamber 2 and a refrigerating chamber 10, and includes a freezing chamber door 21 and a refrigerating chamber door 11 for opening and closing the freezing chamber 20 and the refrigerating chamber 10. Also, a vegetable room 100 for keeping vegetables and fruits (hereinafter, referred to as ‘vegetables’) fresh in storage is provided separately in a certain position of the refrigerating chamber 10.
The vegetable room 100, generally provided in a lower end portion of the refrigerator 1, may include a vegetable box for keeping vegetables and fruits in storage and a cover or a drawer for opening and closing the vegetable box. A cover type vegetable room forms a one-box type vegetable room and a drawer type vegetable room forms a two-box type vegetable room.
In the case in which the vegetable room 100 is formed as a drawer type vegetable room, as illustrated in FIG. 2, the drawer type vegetable room includes a vegetable box 110 and a drawer 130 installed in the vegetable box 110 such that it is drawable.
The vegetable box 110 is formed such that a front side is open. The vegetable box 110 is opened and closed as the drawer 130 is reciprocally inserted through the open front portion in a slidable manner.
The vegetable box 110 is formed with a freezing chamber plate, an external plate, an upper plate, and a lower plate. A rear side of the vegetable box 110 is closed, and a front side thereof is open.
In general, when vegetables are kept in storage in the refrigerator, the vegetables are required to be maintained with optimal freshness, so it is important to maintain the space in which vegetables are received or accommodated under an optimal condition.
The drawer hermetically closes the vegetable box 110 to block an air flow from the outside to maintain humidity of an internal space thereof. In general, the interior of the vegetable room 110 is hermetically closed against the outside to maintain pressure different from external pressure.
Thus, when the vehicle chamber 110 is closed, preferably, the interior of the vehicle chamber is hermetically closed with respect to the exterior and maintained in pressure lower than external pressure. To this end, a vacuum pump is actuated to make the interior of the vegetable room 110 be in a weak vacuum state to maintain pressure lower than atmospheric pressure therein.
As illustrated in FIG. 3, a vacuum pump is actuated to maintain the interior of the vegetable room 110 of the related art at predetermined pressure (e.g., 0.65 atm) as single pressure. When the pressure within the vegetable room 110 reaches the pre-set predetermined pressure, the vacuum pump is turned off, and when the pressure within the vegetable room 110 drops below the pre-set predetermined pressure, the vacuum pump is turned on.
Storage items kept in storage in the vegetable room 100 may include food items with leaves (hereinafter, referred to as ‘vegetables’) such as asparagus, chives, lettuce, spinach, and the like, and food items without leaves (hereinafter, referred to as ‘fruits’) such as potato, watermelon, lemon, apple, orange, white radish, graph, persimmon, tomato, cucumber, pear, carrot, cabbage, and the like.
As illustrated in FIG. 4, in general, vegetables have large leaves to have a large amount of respiration and transpiration, having a high rate of respiration, while fruits without leaves have a small amount of respiration and transpiration, having a low rate of respiration.
As for magnitudes and grades of rates of respiration, as illustrated in FIG. 4, fruits such as dried fruits, garlic, potato, pumpkin, apple, citrus fruits, carrot, cucumber, tomato, pear, cabbage, and the like, have a low grade (equal to or less than 20), while strawberry, chives, lattice, kidney bean, cut flowers, spinach, broccoli, mushroom, and the like, have a high grade (equal to or more than 20).
However, in a case in which the interior of the vegetable room is uniformly maintained at the same pressure, pressures optimized according to different rates of respiration of vegetables and fruits cannot be maintained, making it difficult to maintain optimal freshness of storage items.
Thus, it is required to differentiate pressures within a vegetable room in order to enhance freshness of the vegetable room in which vegetables and fruits are kept in storage.